Cost Benefit Analysis: Hand Drying

Pulling together 12 studies on hand-drying, Mayo Clinic researchers did a cost benefit analysis of paper towels v. hot air. Because they were most concerned with hospitals and other health care facilities, bacteria were a top topic.

Their conclusions…

It was not even close. Cloth and paper towels provide more bacteria protection than a hot air dryer after we wash our hands. One reason is speed. We tend not to wait long enough with hot air to dry our hands and thereby retain more bacteria. Furthermore, the air from a dryer propels bacteria. Specifically, after 10 seconds of drying with a towel, 4% of the water remains. However, it takes 45 seconds with hot air to get the water residue down to 3%. We should note though that jet dryers do dry hands as efficiently as towels but have other hot air costs, people prefer towels, and hot air is probably more environmentally friendly.

Our bottom Line: There is no free lunch. Looking at the world economically involves recognizing the tradeoffs that our decisions necessitate. Whether the subject is hand-drying, federal entitlements or investing, comparing cost and benefit can lead to optimal choices. As always, economics is about a lot more than money.

Sources and Resources: Consistently excellent, the Conversable Economistblog was the source of my hand-drying example and a summary of this Mayo Clinic paper. For part 1 of “Unexpected Economics,” the hand washing section is here.